Email Service

We have a need for a service that runs on windows server 2019. This service need to run on a schedule and send out emails every evening at a specific time. We need the interface to be developed in winforms using dot net 4.8. The back end must be c#. No 3rd party components please! This doesn't need to be a polished and finished program. The user interface will be converted. The user interface is more for setup showing how it works.